WebRTC VAD wrapper for APM-QA

Alternative VAD based on the existing one in WebRTC.
It is used to extract VAD annotations in APM-QA.

TBR=

Bug: webrtc:7494
Change-Id: I6af412742f804631ad4f3ba3ccf71a30d74de984
Reviewed-on: https://webrtc-review.googlesource.com/14553
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Reviewed-by: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20404}

modules/audio_processing/test/py_quality_assessment/BUILD.gn

@@ -102,6 +102,7 @@ group("unit_tests") {
     ":fake_polqa",
     ":lib_unit_tests",
     ":scripts_unit_tests",
+    ":vad",
   ]
 }
 
@@ -118,6 +119,17 @@ rtc_executable("fake_polqa") {
   ]
 }
 
+rtc_executable("vad") {
+  sources = [
+    "quality_assessment/vad.cc",
+  ]
+  deps = [
+    "../../../..:webrtc_common",
+    "../../../../common_audio",
+    "../../../../rtc_base:rtc_base_approved",
+  ]
+}
+
 copy("lib_unit_tests") {
   testonly = true
   sources = [

modules/audio_processing/test/py_quality_assessment/quality_assessment/annotations.py

@@ -10,9 +10,14 @@
 """
 
 from __future__ import division
+import enum
 import logging
 import os
+import shutil
+import struct
+import subprocess
 import sys
+import tempfile
 
 try:
   import numpy as np
@@ -20,6 +25,7 @@ except ImportError:
   logging.critical('Cannot import the third-party Python package numpy')
   sys.exit(1)
 
+from . import exceptions
 from . import signal_processing
 
 
@@ -27,9 +33,12 @@ class AudioAnnotationsExtractor(object):
   """Extracts annotations from audio files.
   """
 
-  _LEVEL_FILENAME = 'level.npy'
-  _VAD_FILENAME = 'vad.npy'
-  _SPEECH_LEVEL_FILENAME = 'speech_level.npy'
+  @enum.unique
+  class VadType(enum.Enum):
+    ENERGY_THRESHOLD = 0  # TODO(alessiob): Consider switching to P56 standard.
+    WEBRTC = 1
+
+  _OUTPUT_FILENAME = 'annotations.npz'
 
   # Level estimation params.
   _ONE_DB_REDUCTION = np.power(10.0, -1.0 / 20.0)
@@ -41,36 +50,50 @@ class AudioAnnotationsExtractor(object):
 
   # VAD params.
   _VAD_THRESHOLD = 1
+  _VAD_WEBRTC_PATH = os.path.join(os.path.dirname(
+      os.path.abspath(__file__)), os.pardir, os.pardir)
+  _VAD_WEBRTC_BIN_PATH = os.path.join(_VAD_WEBRTC_PATH, 'vad')
 
-  def __init__(self):
+  def __init__(self, vad_type):
     self._signal = None
     self._level = None
-    self._vad = None
-    self._speech_level = None
     self._level_frame_size = None
+    self._vad_output = None
+    self._vad_frame_size = None
+    self._vad_frame_size_ms = None
     self._c_attack = None
     self._c_decay = None
 
-  @classmethod
-  def GetLevelFileName(cls):
-    return cls._LEVEL_FILENAME
+    self._vad_type = vad_type
+    if self._vad_type not in self.VadType:
+      raise exceptions.InitializationException(
+          'Invalid vad type: ' + self._vad_type)
+    logging.info('VAD used for annotations: ' + str(self._vad_type))
+
+    assert os.path.exists(self._VAD_WEBRTC_BIN_PATH), self._VAD_WEBRTC_BIN_PATH
 
   @classmethod
-  def GetVadFileName(cls):
-    return cls._VAD_FILENAME
-
-  @classmethod
-  def GetSpeechLevelFileName(cls):
-    return cls._SPEECH_LEVEL_FILENAME
+  def GetOutputFileName(cls):
+    return cls._OUTPUT_FILENAME
 
   def GetLevel(self):
     return self._level
 
-  def GetVad(self):
-    return self._vad
+  def GetLevelFrameSize(self):
+    return self._level_frame_size
 
-  def GetSpeechLevel(self):
-    return self._speech_level
+  @classmethod
+  def GetLevelFrameSizeMs(cls):
+    return cls._LEVEL_FRAME_SIZE_MS
+
+  def GetVadOutput(self):
+    return self._vad_output
+
+  def GetVadFrameSize(self):
+    return self._vad_frame_size
+
+  def GetVadFrameSizeMs(self):
+    return self._vad_frame_size_ms
 
   def Extract(self, filepath):
     # Load signal.
@@ -78,7 +101,7 @@ class AudioAnnotationsExtractor(object):
     if self._signal.channels != 1:
       raise NotImplementedError('multiple-channel annotations not implemented')
 
-    # level estimation params.
+    # Level estimation params.
     self._level_frame_size = int(self._signal.frame_rate / 1000 * (
         self._LEVEL_FRAME_SIZE_MS))
     self._c_attack = 0.0 if self._LEVEL_ATTACK_MS == 0 else (
@@ -91,26 +114,26 @@ class AudioAnnotationsExtractor(object):
     # Compute level.
     self._LevelEstimation()
 
-    # Naive VAD based on level thresholding. It assumes ideal clean speech
-    # with high SNR.
-    # TODO(alessiob): Maybe replace with a VAD based on stationary-noise
-    # detection.
+    # Ideal VAD output, it requires clean speech with high SNR as input.
+    if self._vad_type == self.VadType.ENERGY_THRESHOLD:
+      # Naive VAD based on level thresholding.
       vad_threshold = np.percentile(self._level, self._VAD_THRESHOLD)
-    self._vad = np.uint8(self._level > vad_threshold)
-
-    # Speech level based on VAD output.
-    self._speech_level = self._level * self._vad
-
-    # Expand to one value per sample.
-    self._level = np.repeat(self._level, self._level_frame_size)
-    self._vad = np.repeat(self._vad, self._level_frame_size)
-    self._speech_level = np.repeat(self._speech_level, self._level_frame_size)
+      self._vad_output = np.uint8(self._level > vad_threshold)
+      self._vad_frame_size = self._level_frame_size
+      self._vad_frame_size_ms = self._LEVEL_FRAME_SIZE_MS
+    elif self._vad_type == self.VadType.WEBRTC:
+      # WebRTC VAD.
+      self._RunWebRtcVad(filepath, self._signal.frame_rate)
 
   def Save(self, output_path):
-    np.save(os.path.join(output_path, self._LEVEL_FILENAME), self._level)
-    np.save(os.path.join(output_path, self._VAD_FILENAME), self._vad)
-    np.save(os.path.join(output_path, self._SPEECH_LEVEL_FILENAME),
-            self._speech_level)
+    np.savez_compressed(
+        file=os.path.join(output_path, self._OUTPUT_FILENAME),
+        level=self._level,
+        level_frame_size=self._level_frame_size,
+        level_frame_size_ms=self._LEVEL_FRAME_SIZE_MS,
+        vad_output=self._vad_output,
+        vad_frame_size=self._vad_frame_size,
+        vad_frame_size_ms=self._vad_frame_size_ms)
 
   def _LevelEstimation(self):
     # Read samples.
@@ -132,4 +155,47 @@ class AudioAnnotationsExtractor(object):
           self._level[i], self._level[i - 1], self._c_attack if (
               self._level[i] > self._level[i - 1]) else self._c_decay)
 
-    return self._level
+  def _RunWebRtcVad(self, wav_file_path, sample_rate):
+    self._vad_output = None
+    self._vad_frame_size = None
+
+    # Create temporary output path.
+    tmp_path = tempfile.mkdtemp()
+    output_file_path = os.path.join(
+        tmp_path, os.path.split(wav_file_path)[1] + '_vad.tmp')
+
+    # Call WebRTC VAD.
+    try:
+      subprocess.call([
+          self._VAD_WEBRTC_BIN_PATH,
+          '-i', wav_file_path,
+          '-o', output_file_path
+      ], cwd=self._VAD_WEBRTC_PATH)
+
+      # Read bytes.
+      with open(output_file_path, 'rb') as f:
+        raw_data = f.read()
+
+      # Parse side information.
+      self._vad_frame_size_ms = struct.unpack('B', raw_data[0])[0]
+      self._vad_frame_size = self._vad_frame_size_ms * sample_rate / 1000
+      assert self._vad_frame_size_ms in [10, 20, 30]
+      extra_bits = struct.unpack('B', raw_data[-1])[0]
+      assert 0 <= extra_bits <= 8
+
+      # Init VAD vector.
+      num_bytes = len(raw_data)
+      num_frames = 8 * (num_bytes - 2) - extra_bits  # 8 frames for each byte.
+      self._vad_output = np.zeros(num_frames, np.uint8)
+
+      # Read VAD decisions.
+      for i, byte in enumerate(raw_data[1:-1]):
+        byte = struct.unpack('B', byte)[0]
+        for j in range(8 if i < num_bytes - 3 else (8 - extra_bits)):
+          self._vad_output[i * 8 + j] = int(byte & 1)
+          byte = byte >> 1
+    except Exception as e:
+      logging.error('Error while running the WebRTC VAD (' + e.message + ')')
+    finally:
+      if os.path.exists(tmp_path):
+        shutil.rmtree(tmp_path)

modules/audio_processing/test/py_quality_assessment/quality_assessment/annotations_unittest.py

@@ -9,6 +9,7 @@
 """Unit tests for the annotations module.
 """
 
+from __future__ import division
 import logging
 import os
 import shutil
@@ -27,6 +28,7 @@ class TestAnnotationsExtraction(unittest.TestCase):
   """
 
   _CLEAN_TMP_OUTPUT = True
+  _DEBUG_PLOT_VAD = False
 
   def setUp(self):
     """Create temporary folder."""
@@ -36,6 +38,7 @@ class TestAnnotationsExtraction(unittest.TestCase):
         'pure_tone', [440, 1000])
     signal_processing.SignalProcessingUtils.SaveWav(
         self._wav_file_path, pure_tone)
+    self._sample_rate = pure_tone.frame_rate
 
   def tearDown(self):
     """Recursively delete temporary folder."""
@@ -45,27 +48,49 @@ class TestAnnotationsExtraction(unittest.TestCase):
       logging.warning(self.id() + ' did not clean the temporary path ' + (
           self._tmp_path))
 
-  def testExtraction(self):
-    e = annotations.AudioAnnotationsExtractor()
+  def testFrameSizes(self):
+    for vad_type in annotations.AudioAnnotationsExtractor.VadType:
+      e = annotations.AudioAnnotationsExtractor(vad_type=vad_type)
       e.Extract(self._wav_file_path)
-    vad = e.GetVad()
-    assert len(vad) > 0
-    self.assertGreaterEqual(float(np.sum(vad)) / len(vad), 0.95)
+      samples_to_ms = lambda n, sr: 1000 * n // sr
+      self.assertEqual(samples_to_ms(e.GetLevelFrameSize(), self._sample_rate),
+                       e.GetLevelFrameSizeMs())
+      self.assertEqual(samples_to_ms(e.GetVadFrameSize(), self._sample_rate),
+                       e.GetVadFrameSizeMs())
+
+  def testVoiceActivityDetectors(self):
+    for vad_type in annotations.AudioAnnotationsExtractor.VadType:
+      e = annotations.AudioAnnotationsExtractor(vad_type=vad_type)
+      e.Extract(self._wav_file_path)
+      vad_output = e.GetVadOutput()
+      self.assertGreater(len(vad_output), 0)
+      self.assertGreaterEqual(float(np.sum(vad_output)) / len(vad_output), 0.95)
+
+      if self._DEBUG_PLOT_VAD:
+        frame_times_s = lambda num_frames, frame_size_ms: np.arange(
+            num_frames).astype(np.float32) * frame_size_ms / 1000.0
+        level = e.GetLevel()
+        t_level = frame_times_s(
+            num_frames=len(level),
+            frame_size_ms=e.GetLevelFrameSizeMs())
+        t_vad = frame_times_s(
+            num_frames=len(vad_output),
+            frame_size_ms=e.GetVadFrameSizeMs())
+        import matplotlib.pyplot as plt
+        plt.figure()
+        plt.hold(True)
+        plt.plot(t_level, level)
+        plt.plot(t_vad, vad_output * np.max(level), '.')
+        plt.show()
 
   def testSaveLoad(self):
-    e = annotations.AudioAnnotationsExtractor()
+    e = annotations.AudioAnnotationsExtractor(
+        vad_type=annotations.AudioAnnotationsExtractor.VadType.ENERGY_THRESHOLD)
     e.Extract(self._wav_file_path)
     e.Save(self._tmp_path)
 
-    level = np.load(os.path.join(self._tmp_path, e.GetLevelFileName()))
-    np.testing.assert_array_equal(e.GetLevel(), level)
-    self.assertEqual(np.float32, level.dtype)
-
-    vad = np.load(os.path.join(self._tmp_path, e.GetVadFileName()))
-    np.testing.assert_array_equal(e.GetVad(), vad)
-    self.assertEqual(np.uint8, vad.dtype)
-
-    speech_level = np.load(os.path.join(
-        self._tmp_path, e.GetSpeechLevelFileName()))
-    np.testing.assert_array_equal(e.GetSpeechLevel(), speech_level)
-    self.assertEqual(np.float32, speech_level.dtype)
+    data = np.load(os.path.join(self._tmp_path, e.GetOutputFileName()))
+    np.testing.assert_array_equal(e.GetLevel(), data['level'])
+    self.assertEqual(np.float32, data['level'].dtype)
+    np.testing.assert_array_equal(e.GetVadOutput(), data['vad_output'])
+    self.assertEqual(np.uint8, data['vad_output'].dtype)

modules/audio_processing/test/py_quality_assessment/quality_assessment/simulation.py

@@ -46,7 +46,8 @@ class ApmModuleSimulator(object):
     self._evaluation_score_factory = evaluation_score_factory
     self._audioproc_wrapper = ap_wrapper
     self._evaluator = evaluator
-    self._annotator = annotations.AudioAnnotationsExtractor()
+    self._annotator = annotations.AudioAnnotationsExtractor(
+        vad_type=annotations.AudioAnnotationsExtractor.VadType.WEBRTC)
 
     # Init.
     self._test_data_generator_factory.SetOutputDirectoryPrefix(

modules/audio_processing/test/py_quality_assessment/quality_assessment/vad.cc

@@ -0,0 +1,100 @@
+// Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS.  All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+
+#include <array>
+#include <fstream>
+#include <memory>
+
+#include "common_audio/vad/include/vad.h"
+#include "common_audio/wav_file.h"
+#include "rtc_base/flags.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+
+// The allowed values are 10, 20 or 30 ms.
+constexpr uint8_t kAudioFrameLengthMilliseconds = 30;
+constexpr int kMaxSampleRate = 48000;
+constexpr size_t kMaxFrameLen =
+    kAudioFrameLengthMilliseconds * kMaxSampleRate / 1000;
+
+constexpr uint8_t kBitmaskBuffSize = 8;
+
+DEFINE_string(i, "", "Input wav file");
+DEFINE_string(o, "", "VAD output file");
+
+int main(int argc, char* argv[]) {
+  if (rtc::FlagList::SetFlagsFromCommandLine(&argc, argv, true))
+    return 1;
+
+  // Open wav input file and check properties.
+  WavReader wav_reader(FLAG_i);
+  if (wav_reader.num_channels() != 1) {
+    LOG(LS_ERROR) << "Only mono wav files supported";
+    return 1;
+  }
+  if (wav_reader.sample_rate() > kMaxSampleRate) {
+    LOG(LS_ERROR) << "Beyond maximum sample rate (" << kMaxSampleRate << ")";
+    return 1;
+  }
+  const size_t kAudioFrameLen = rtc::CheckedDivExact(
+      kAudioFrameLengthMilliseconds * wav_reader.sample_rate(), 1000);
+  if (kAudioFrameLen > kMaxFrameLen) {
+    LOG(LS_ERROR) << "The frame size and/or the sample rate are too large.";
+    return 2;
+  }
+
+  // Create output file and write header.
+  std::ofstream out_file(FLAG_o, std::ofstream::binary);
+  const char audio_frame_length_ms = kAudioFrameLengthMilliseconds;
+  out_file.write(&audio_frame_length_ms, 1);  // Header.
+
+  // Run VAD and write decisions.
+  std::unique_ptr<Vad> vad = CreateVad(Vad::Aggressiveness::kVadNormal);
+  std::array<int16_t, kMaxFrameLen> samples;
+  char buff = 0;     // Buffer to write one bit per frame.
+  uint8_t next = 0;  // Points to the next bit to write in |buff|.
+  while (true) {
+    // Process frame.
+    const auto read_samples =
+        wav_reader.ReadSamples(kAudioFrameLen, samples.data());
+    if (read_samples < kAudioFrameLen)
+      break;
+    const auto is_speech = vad->VoiceActivity(samples.data(), kAudioFrameLen,
+                                              wav_reader.sample_rate());
+
+    // Write output.
+    buff = is_speech ? buff | (1 << next) : buff & ~(1 << next);
+    if (++next == kBitmaskBuffSize) {
+      out_file.write(&buff, 1);  // Flush.
+      buff = 0;                  // Reset.
+      next = 0;
+    }
+  }
+
+  // Finalize.
+  char extra_bits = 0;
+  if (next > 0) {
+    extra_bits = kBitmaskBuffSize - next;
+    out_file.write(&buff, 1);  // Flush.
+  }
+  out_file.write(&extra_bits, 1);
+  out_file.close();
+
+  return 0;
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace webrtc
+
+int main(int argc, char* argv[]) {
+  return webrtc::test::main(argc, argv);
+}